1. Field
The described technology relates generally to an organic light emitting diode (OLED) display.
2. Description of the Related Art
An organic light emitting diode (OLED) display is provided with a plurality of pixels, each including an organic light emitting diode and a driving circuit, to display an image. The organic light emitting diode is formed of a pixel electrode, a common electrode, and an organic emission layer between the pixel electrode and the common electrode.
Because a display function and a life-span characteristic are deteriorated when the organic light emitting element is exposed to external moisture and oxygen, an encapsulation layer is formed on the display portion to seal the display portion for reducing or blocking inflow of external air. For this, an encapsulation substrate is provided on an upper portion of a display area on the substrate, and a sealant is provided along an inner edge of the encapsulation substrate that faces toward the substrate so as to substantially seal the display area.
The sealant is formed by a frit melted by a laser beam and then cured. The laser beam used in a sealing process has Gaussian-shaped energy dispersion, and the laser beam is sequentially irradiated along a clockwise or counterclockwise direction from one point of the frit while a laser head emitting a laser beam or a stage supporting the substrate is moving.
However, the laser beam having the Gaussian dispersion has non-uniform energy dispersion at a cross-section thereof, thereby causing deterioration of shape uniformity of the sealant. In addition, the laser beam is irradiated along the plane shape of the sealant and thus energy difference occurs in inner and outer sides of the sealant during a curing process after melting, thereby causing generation of cracks. Here, the inner side of the sealant is an inner side facing the display area. The shape non-uniformity of the sealant and generation of cracks deteriorate sealing performance of the sealant, and the problems need to be solved.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.